Summary The Cessna U206F floatplane, registration C-FMGP, serial number U20602839, operated by Aviation Mauricie, was on a visual flight rules flight with one pilot, one student pilot and one passenger on board. At about 1125eastern daylight time, the aircraft took off from Pasteur Lake, Quebec, and flew at low altitude over the water for a few seconds. About 30feet above the surface of the lake, the aircraft made a 90left turn and headed directly towards the departure wharf where the owners were. At about 100feet above the wharf, the aircraft was seen in a nose-up attitude and appeared unstable. Shortly after, the right wing pointed towards the ground, and the aircraft pitched nose down and crashed into the trees about 300feet farther south. A witness rushed to the crash site. Smoke was coming from the wreckage. Several minutes later, flames appeared at the right wing root. The fire could not be brought under control with a fire extinguisher, and spread to the cabin and the rest of the aircraft. The three occupants sustained fatal injuries. Ce rapport est galement disponible en franais. Other Factual Information At approximately 0940 eastern daylight time1 on the morning of the accident, the floatplane took off from Tortue Lake, Quebec, Aviation Mauricie's main base. The planned flight consisted of a return flight with stops at Pasteur Lake, Quebec, and Taureau Reservoir, Quebec. At 1020, the floatplane docked at a wharf located on the eastern shore of Pasteur Lake. The occupants spent some time with the owner of the premises, who was a friend of the pilot. Topographic map of Pasteur Lake The owner of the wharf had a floatplane that he used regularly to travel between Tortue Lake and Pasteur Lake. Before departure, he informed the occurrence pilot of the take-off flight path preferred by other pilots familiar with Pasteur Lake. It consisted in starting the take-off run from the far north end of the lake heading in a southwesterly direction, and after lift off, it was necessary to make a slight turn to the left to continue to climb in the saddle between the two mountains bordering the southern section of the lake (see Figure1). At about 1100, the pilot got into the right front seat, the student pilot got into the left front seat and the passenger sat in the right back seat. At approximately 1112, the aircraft left the wharf and taxied on the water towards the northern section of the lake. The floatplane disappeared behind a peninsula (see Figure1) and shortly after started its take-off run towards the southwest. Rather than following the suggested flight path, the aircraft took off more or less into the wind in a southwesterly direction. Shortly after becoming airborne near the western shore of the lake, the aircraft turned left heading east with a tailwind, and headed directly towards the departure wharf (see Photo1). About 1700feet separated the two shores of the lake where the turn was made. After flying over the wharf, the aircraft stalled and crashed 300feet to the south. The engine continued to operate for a short time. View of the location where the floatplane turned towards the wharf after becoming airborne The pilot was certified and qualified for the flight in accordance with existing regulations. He held a commercial pilot licence (aeroplane) since 12July2004. He started working for Aviation Mauricie in July2004. After being hired, he received, amongst other things, training on floatplanes and on the Cessna206. The data available indicate that the pilot had accumulated approximately 1000flying hours. It was the first time that he landed on Pasteur Lake. Although he did not have an instructor rating, the pilot could give training on floatplanes. The pilot, as pilot in command, was responsible for the conduct of the flight. The student pilot held a private pilot licence (aeroplane) issued in October1989 by the Direction Gnrale de l'Aviation Civile in France. He had accumulated 1226 flying hours and was endorsed on single-engine and multi-engine aircraft and seaplanes with a maximum take-off weight of 2700kg or less. However, his classH seaplane endorsement issued in 1993in Guyana was not valid at the time of the incident. His French medical certificate was valid until 30September2006. Transport Canada had issued a Foreign Licence Validation Certificate on 28June2005 valid until 01July2006. The certificate had not been renewed. On 10 April 2006, the student pilot had purchased a block of 40 flying hours from Aviation Mauricie for floatplane training. He had accumulated 14.5flying hours on C-FMGP since 25June2006. The company had no training file for the student pilot and was not required to keep one. At the time of the accident, the weather conditions were favourable for visual flight. There were few clouds and the temperature was 26C. The wind was from the southwest at 15knots with gusts up to 25knots. Waves of 20to 25cm stirred the surface of the lake. The Cessna U206F is a high-wing, single-engine aircraft, with seating capacity of up to six people. The aircraft may be flown from the left or right seat. However, the pilot flying usually occupies the left seat. The aircraft journey logbook was not recovered. It was probably destroyed in the post-impact fire. The aircraft technical logbooks were examined to assess the floatplane's airworthiness. The aircraft had undergone a 200-hour recurrent inspection on 19May2006 and was found to be airworthy. The aircraft was certified, equipped, and maintained in accordance with existing regulations and approved procedures. The weight and balance of the aircraft were calculated using the estimated weight of the occupants and the estimated amount of fuel on board. There was no luggage on board. The aircraft weight at the time of the crash was about 3300pounds, that is, 300pounds less than the maximum allowable weight of 3600pounds. According to calculations, the aircraft centre of gravity was within the specified limits. The pilot had completed the weight and balance form for the aircraft published in the company operations manual. The investigation revealed that the form used for the aircraft wrongfully indicated that the maximum allowable weight for the aircraft was 3800pounds. However, the mistake on the form had no impact on the accident. According to the aircraft flight manual, for a floatplane at this estimated weight and balance, using 20of flap and 0 of bank angle, the stall speed is around 50knots. The aircraft was equipped with a stall warning system that provided an audible warning. The stall warning system's horn is activated when the aircraft's speed is 5to 10knots above the stall speed. According to Cessna, the optimal rate of climb on take-off using 20 of flap obtained during flight tests is 625feet per minute. This rate is obtained in the following configuration: full throttle with an indicated airspeed of 76knots. This rate of climb corresponds to an angle of climb of about 5 with no wind. The angle is steeper with a headwind and less steep with a tailwind. The aircraft climb performance is reduced when the suggested speed is not maintained. However, when it is necessary to clear an obstacle after take-off, the aircraft flight manual suggests using the best climb angle speed of 63knots and 20offlap. In some situations, a pilot's ability to estimate speed, size, distance, the direction to a slope, or even to identify objects can be seriously diminished. Pilots can be subjected to optical illusions when approaching a rising slope at right angles. When getting close to the ridge, the pilot may tend to maintain a constant angle between the extended cowl and the mountain peak; as a result, the pitch attitude of the aircraft increases and speed decreases (see Figure2). Consequently, aircraft performance decreases and vertical separation with the terrain decreases. Possible optical illusion when approaching a rising slope Also, the proximity of the ground tends to hold the pilot's attention and, as a result, can affect the flying of the aircraft. The illusion of increasing speed in relation to the ground in tailwind conditions is easily noticeable, to the point where the pilot may be tempted to reduce speed. The aircraft crashed on the eastern shore of Pasteur Lake at about 15feet above the water level. The wreckage was found at the bottom of a 300-foot hill that has a slope of almost 11. As the aircraft descended, it severed trees for about 40feet before striking the ground. Based on the marks on the trees and the aircraft damage, the floatplane had a right roll attitude of about 110 and was in a steep nose-down attitude before striking the ground. The aircraft came to rest on its back. The impact damage and the nose-down attitude of the wreckage are consistent with a loss of control following a stall. An integral fuel tank was located in each wing near the wing root. The right wing had electrical wiring to operate the position light, flap motor and fuel quantity indicator. A fire broke out about five minutes after the crash. The entire aircraft, except the left float, the wingtips and the empennage, was consumed by fire. The right side of the aircraft appeared to have sustained the most heat damage. The wings were burned in the area of the integral fuel tanks. The flaps were extended at 20. On a CessnaU206F, this is the normal setting for take-off. The instrument panel melted in the intense heat of the fire; as a result, it was not possible to determine the condition and operational capabilities of the aircraft systems and their components, or the positions of any controls, switches or indicators. However, examination of all components recovered revealed no pre-impact failures or malfunctions. The flight control system sustained substantial damage, but flight control continuity was established. All failures were due to overload. The trees severed by the propeller blades and the blade damage indicate that the engine was producing power on impact. Part of the aircraft engine casing had melted. The propeller was sheared from the engine; all the engine crankshaft plate mounting bolts had failed in tension. The examination could not precisely determine the engine power. However, surrounding trees showed propeller strike marks indicating that the propeller was rotating. Examination of the wreckage revealed no evidence of any airframe failure, flight control problems, electrical problems, power loss, or fire during the flight. Due to the condition of the instruments, it was not possible to determine the instrument readings at the time of impact. From examination of the wreckage, it was not possible to determine the position of the engine controls and fuel tank selector, or the condition of the seat belt attachments and the adjustment of the seat belts. The emergency locator transmitter (ELT), Technisonic model TEL-82, serial number12127, was not found in the burnt wreckage. Since the ELTis made almost entirely of plastic, it is likely that it was completely destroyed by heat. According to the aircraft's records, the ELT was installed in accordance with existing regulations. The cockpit was severely damaged on impact, and the space for the front occupants was reduced to practically nothing. The cabin was then completely destroyed by the post-impact fire. Although the three occupants were wearing their seat belts, the accident was not survivable. Autopsies and toxicological tests were done on the three occupants. In all three cases, the cause of death was determined to be multiple traumatic injuries. According to the autopsy and toxicological test results, there was no indication that incapacitation affected the pilot's performance. The autopsy performed on the student pilot who was in the front seat revealed the presence of coronary heart disease, but no recent indications of thrombosis or infarction were observed.